2006 250ex jetting question

[BigPapa]

Okay, here is the scoop -
2006 TRX250EX
Uni Filter
Airbox lid on (want to keep it on)
FMF Powercore Slip On
100 main jet
adjustable needle from a Dyno-kit on 4th setting
The bike ran real good until I put on the FMF
It tends to pop on decel since I installed the exhaust. When I pull the choke all the way out (not that I need to), the bike stalls/dies
My question should an Air/Fuel screw adjustment fix this problem or should I go up to a 105 main jet?
Anybody out there running this set up?
Any help would be great. I ride at sea-level.

[Goose]

it may be running rich. is that carb jet aftermarket??

[Here 2 help]

It's going lean on throttle closing due to the low restriction exhaust. You probably won't cure it completely, but back the fuel screw out about 1/2 to 1 turn and increase the idle speed.